1. Field of the Invention
The present invention relates to a liquid crystal display panel and fabricating method thereof suitable for preventing spot degradation on a periphery of an image display part displaying an image of a unit liquid crystal display panel.
2. Discussion of the Related Art
Generally, a liquid crystal display device supplies liquid crystal cells arranged like a matrix with data signals according to image information respectively to display a demanded image by controlling a light-transmittance of each of the liquid crystal cells.
The liquid crystal display device includes a liquid crystal display panel having pixel unit liquid crystal cells arranged in a matrix and a driver integrated circuit (IC) for driving the liquid crystal cells.
The liquid crystal display panel includes a color filter substrate, a thin film transistor array substrate confronting the color filter substrate, and a liquid crystal layer filling a space between the color filter and thin film transistor array substrates.
On the thin film transistor array substrate of the liquid crystal display panel, data lines for transmitting data signals supplied from a data driver integrated circuit to the liquid crystal cells cross with gate lines for transmitting scan signals supplied from a gate driver integrated circuit to the liquid crystal cells, respectively. The liquid crystal cells are formed at crossings of the data and gate lines, respectively. Moreover, data and gate pads, to which the data and scan signals are applied from the data and gate driver integrated circuits, respectively, are formed at ends of the data and gate lines, respectively.
The gate driver integrated circuit sequentially supplies the scan signals to the gate lines to select the matrix-like arranged liquid crystal cells one by one. The data signal is applied to the liquid crystal cells on each of the selected lines from the data driver integrated circuit.
Meanwhile, a common electrode and pixel electrodes are formed on inner surfaces of the color filter and thin film transistor array substrates facing each other, respectively to apply an electric field to the liquid crystal layer. In this case, the pixel electrodes are formed in the liquid crystal cells of the thin film transistor array substrate, respectively. Yet, the common electrode is built in one body on the entire surface of the color filter substrate. Hence, one voltage applied to each of the pixel electrodes is controlled while the other voltage is applied to the common electrode, thereby enabling the control of light transmittance of each of the liquid crystal cells individually.
Moreover, a thin film transistor used as a switching device is formed in each of the liquid crystal cells. In the liquid crystal cell having a gate electrode of the thin film transistor supplied with the scan signal through the gate line, a conductive channel is generated between source and drain electrodes of the thin film transistor. In this case, the data signal applied to the source electrode of the thin film transistor through the data line is applied to the corresponding pixel electrode via the drain electrode of the thin film transistor, whereby the electric field is applied to the liquid crystal layer of the corresponding liquid crystal cell.
The above-described liquid crystal display panel is explained in detail as follows.
FIG. 1 illustrates a schematic layout of a unit liquid crystal display panel constructed with a thin film transistor array substrate and a color filter substrate bonded to each other to confront according to a related art.
Referring to FIG. 1, a unit liquid crystal display panel 10 includes an image display part 13 having liquid crystal cells arranged in a matrix form, a gate pad part 14 connecting gate lines GL1˜GLm of the image display part 13 to a gate driver integrated circuit (not shown in the drawing) supplying gate signals, and a data pad part 15 connecting data lines DL1˜DLn of the image display part 13 to a data driver integrated circuit (not shown in the drawing) supplying image information. In this case, the gate and data pad parts 14 and 15 are formed on edge areas of a thin film transistor array substrate 1 having one long and one short side protruding from the sides of the color filter substrate 2.
In this case, in areas provided by the data and gate lines DL1˜DLn and GL1˜GLm crossing with each other on the thin film transistor array substrate 1, thin film transistors are formed to switch liquid crystal cells, respectively, pixel electrodes are connected to the thin film transistors to apply electric fields to the corresponding liquid crystal cells, and a passivation layer is formed on an entire surface to protect the data lines DL1˜DLn, gate lines GL1˜GLm, thin film transistors, and electrodes.
On the color filter substrate 2 color filters are formed coated thereon to separate by each cell area through a black matrix and a common electrode as a counter electrode of the pixel electrodes on the thin film transistor array substrate 1.
A cell gap is provided by the above-constructed thin film transistor array and color filter substrates 1 and 2 leaving a predetermined interval from each other. The thin film transistor array and color filter substrates 1 and 2 are bonded to each other by a sealing part (not shown in the drawing) formed on a periphery of the image display part 13. A liquid crystal layer (not shown in the drawing) is formed in a separating space between the thin film transistor array and color filter substrates 1 and 2.
Meanwhile, a dummy area 16 is formed on the periphery of the image display part 13 to provide a predetermined margin in combining the unit liquid crystal display panel 10 with a backlight assembly or an exterior frame.
In order to prevent light from leaking through edges of the unit liquid crystal display panel 10 when the light emitted from the backlight assembly is transmitted to the dummy area 16, a material such as a black matrix is coated on the dummy area 16.
FIG. 2 illustrates a cross-sectional view of the dummy area 16 of the unit liquid crystal display panel 10 along a cutting line I-I′ in a direction in parallel with a short side of the unit liquid crystal display panel 10 in FIG. 1, in which a gate pad part 14 is generally formed on one of the short sides of the unit liquid crystal display panel 10.
Referring to FIG. 2, a thin film transistor array substrate 11 includes gate lines GL11 and GL12 patterned separate from each other on a first substrate 21, a gate insulating layer 22 over an entire surface of the first substrate 21 including the gate lines GL11 and GL12, and a passivation layer 23 on the gate insulating layer 22.
A color filter substrate 12 includes a black matrix 32 on a second substrate 31 to face the passivation layer 23 of the thin film transistor array substrate 11.
The thin film transistor array and color filter substrates 11 and 12 are bonded to face each other by being separated with a predetermined cell gap. A liquid crystal layer 17 is formed in a space between the thin film transistor array and color filter substrates 11 and 12.
FIG. 3 illustrates a cross-sectional view of the dummy area 16 of the unit liquid crystal display panel 10 along a cutting line II-II′ in a direction in parallel with a long side of the unit liquid crystal display panel 10 in FIG. 1, in which a data pad part 15 is generally formed on one of the long sides of the unit liquid crystal display panel 10.
Referring to FIG. 3, a thin film transistor array substrate 11 includes a gate insulating layer 22 over an entire surface of the first substrate 21, data lines DL11 and DL12 patterned separate from each other on the gate insulating layer 22, and a passivation layer 23 over an entire surface of the first substrate 21 including the data lines DL11 and DL12.
A color filter substrate 12 includes a black matrix 32 on a second substrate 31 to face the passivation layer 23 of the thin film transistor array substrate 11.
The thin film transistor array and color filter substrates 11 and 12 are bonded to face each other by being separated with a predetermined cell gap. A liquid crystal layer 17 is formed in a space between the thin film transistor array and color filter substrates 11 and 12.
As mentioned in the foregoing explanation, the black matrix coated on the color filter substrate 12 blocks the light in order to prevent the light from leaking through edges of the unit liquid crystal display panel 10 according to the related art when the light emitted from the backlight assembly beneath the thin film transistor array substrate 11 is transmitted to the dummy area 16.
Thus, even if the liquid crystal display panel according to the related art includes the black matrix coated on the color filter substrate 12 to block the light emitted from the backlight assembly beneath the thin film transistor array substrate 11 so as not to transmit to the dummy area, spot degradation occurs in the dummy area of the liquid crystal display panel when the black matrix is scratched or particles adhere to or are detached from the black matrix. Hence, the quality of display is degraded.
Moreover, the spot degradation distributed irregularly on the dummy area is difficult to check as well as time taken for such a check is delayed, whereby productivity is reduced.